Wall and ceiling of auditoriums and the like.



W. G. SABINE & R. GU'ASTAVINO. WALL AND CEILING OF AUDITORIUMS AND THELIKE. APPLICATION FILED PEB.17, 1913.

1,1 19,543. Patented Dec. 1,1914.

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UNITED "STATES OFFICE.

.WALLAGE CLEMENT SABINE, OF BOSTON, MASSACHUSETTS, ALE) RAFAELGUASTAVINO, OF BROOKLYN, NEW YORK.

.WALL AND CEILING OF AUDITOBIUMS AND THE LIKE.

Specification of Letters Patent.

- Application filed February 17, 1913. Serial No. 748,943.

To'all'whom it may concern:

Be it known thatwe, WALLAonCmMEN SABINE, a citizen of the United States,residing-in Boston, in the county of Sufiolk and State of Massachusetts,and RAFAEL GUASTAVINO, a citizen of the United States, residing inBrooklyn, in the county of Queens and State of New York, have invented anew and useful Improvement in Walls and Ceilings of Auditoriums and thelike. The object of our invention is to provide walls and ceilings inauditoriums and the like which shall correct certain types of acousticaldifliculties by the prevention, when properly used, of excessivereverberation and echo, and injurious focusing of sound.

This invention is'the result of a request from architects for structuralwalls and ceilings, which shall'be at the same time finished inappearance and acoustically corrective.

In 1900, Wallace Clement Sabine, one of thev applicants herein,published in The- Ameflcan Architect the result of personalinvestigations showing that certaintypes of acoustical difliculties inauditoriums could be corrected by the use of fabrics, such as felt,uncovered or covered with denim, burlap, or the ,like. From that time tothe present manyof the acoustical difficulties in auditoriums have beencorrected by this method. All structural walls and ceilings heretoforein use, such asbrick, tile, wood sheathing, plaster on wood or wirelath, and plaster applied directly to a solid support, are practicallyimpervious to sound waves, and the diminution of incident sound isalmost wholly due to the flexibility of such 'strii'ctures, and suchflexibility is so slight that for the purpose of correcting acousticaldifliculties they are practically non-absorbent. All such previouslyknown structural walls and ceilings reflect at least ninety per centumof the incident sound, and in the great majority of cases more thanninety- .five per centum, the loss of the remaining sound being duealmost wholly to the yieldoctaves above middle C. Although the funpitchof themale speakmgvoice is below middle O, the characteristic sounds jwhlch distinguish articulate speech he mainly within this range.

' Accordingly, the invention pnimarily-consists in a porous artificialmasonry material capable of absorbing sound waves to a very high degree,and hence being specially adapted for the interior exposed face of theiryliills and ceilings of auditoriums and the Also, the inventioncontemplates a novel wall or ceiling structure embodying the improvedmaterial as the inner exposed layer thereof.

. Further objects and advantages of the invention, in its aforesaidseveral aspects, will more readily appear as the description thereofproceeds, and in the accompanyingillustrative drawings.

Figure 1 is a diagram plotting the power for absorbing sounds by thestructure which is the result of this invention, in contrast with thesound-absorbing power of typical standard masonry structures, simple andcompound. Figs. 2 and 3 are sectional views of walls constructed inaccordance with our invention. Fig. 4 shows a section of a wall archconstructed 1n accordance with our mvention.

First referring to these illustrations, it

but like brick, is practically non-absorbent through porosity. Curve 3shows the absorbing power of a plaster on lath wall, in which theresonance for the 'lower notes is apparent. Curve 4 shows the superioracoustic eifect actually obtained by using the construction described inthis invention.

In Fig. 2 we have shown a structural wall jl, to which is secured-alayer of hollow Patented Dec. 1, 1914.

Suchtile is a little more yielding than brick,

blocksB by means of cement or other suitnot porous, in the sense inwhich the word able binding material. To the interior surface of thehollow blocks is secured, by

means of cement or other suitable binding materlal, our poroussound-absorbing material 2, which forms the interior exposed surface ofthe wall.

In Fig. 4 we have shown a structural vaulted ceiling 1, to which issecured, by a suitable binding material such as cement, our poroussound-absorbing material'2.

' From the foregoing it will be seen that in the adaptation of ourimproved'porous material to a Wall or ceiling structure, the innerlayer, directly exposed to the sound, is of masonryQhighly andpeculiarly porous, in such a manner as to make it absorbent of sound,and the outer layer ofwhich is designed for heavy pressure andstructural support.

We pfovideone innerlayer ofmasonry material structurally 'rigid in itsown interior formation, and structurally-a part of the walk It may havea finished and-decoratire surface, and must be suitable for interiorexposure, suitability for such direct interior exposure being necessaryto the present invention. The outer layer may be either solid masonry orhollow-for heat and moisture insulation. Its primary purpose is that ofsupporting the superstructure.

. It is not sufficient for the. purposes of this invention that thepeculiar porosity of the inner layer above referred to consist merely oflnclosed air spaces. Suchstructure is in reality cellular and :withoutvalue'for. thepurpose ofthis invention. The air spaces may beconnecting--and mustconstitute channels traversing the rigid structure of theporous-layer, and reaching to and penetrating the interior surface. Itis desirable that these channels be irregular in form, ex-

panding and contracting in cross-sectiomlso that their action will be.like the mufiiin-g action ofa muflier on; an engine exhaust. Also, itis essential that the pores intercommumcate and openly penetrate theexposed face or faces of the body and shall be of such.

.proportional and variant dimensions'that said bodyshall possess theproperty of absorbmg in excess of ten per centum of sounds lying 1npitch a between middle 0 and the third octave above'middle 0. Hence, the

body of material, generally stated, is sponge-' like insstructure;

Thus, by porosity we do not mean the vcellular structure that exists inthe commercialrporousblock used for insulating for heat and sound. It isessential to this'invention that the sound penetrate thematerial. Anystructure which is useful minsulation must be impervious to air, andtherefore unsuitable toythis invention. The porousrblock used :forasouadmid heat insurlation, 1s, 1ntheony and. iniacneellulals and is here usen I The new material hereindescribed may be made in different ways, butfor illustrative purposes one practical method formaking such materialis given in the following description: Clay, flux, such as feldspar,anda vegetable bearing earth, in a slightly moist condition, arepulverized and thoroughly mixed. \Ve have found that the proportionatesize or dimensions of the I pores and their consequent power to absorbsounds differing in pitch may be varied and determined according .to thedegree of pulverization. In this powdered and slightly moistconditionthe material is then screened with a screen about sixteen meshes to aninch. The powdered material is then placed in' molds of suitable formand subjected. to sufficient pressure to cause the-particles. to cohereThe blanks are then dried, after which they are placed in a suitablekiln,

the temperature of which. is slowly raised of the .tile whenit isincorporated into the wall of a structure'or upon the.upper.face of thematerial! as it lies in the mold.

We have found in our experience that the blanks cannot be satisfactorilyformed in a press from which the material is ex.- uded, as the rubbingof thematerials against the walls of the dies tends to closethe'surface-pores, which renders the finished material entirelyunsuitable forour. purposes. a We have found thatthe best ratioin whichthe three-components should beused varies somewhat with the kind ofclaysand .earthusedi With our particular materials the followingratiosgive very satisfactory results.v Clav 25%, vegetable bearing earth 65%and feldspar 10%.

The advantages of a wall constructed in accordance with-our inventionare that the desired absorption of sound and the correction ofacoustical difficulties is obtained by its use, while at the same timeit is'stru'ctural in its nature, and forms a permanent fireproof wall orceiling, which has to the eye the appearance of solid masonry or "stone,and which may be readily cleaned Wedaim:

1; A sound absorbing wall or ceiling, iiieluding a ceramic materialwhose body has an exposed finished face and is provided throughout withintercommunicating pores which openly penetrate said exposed finishedface.

2. A sound absorbing wall or ceiling, in cluding a ceramic materialwhose body has an exposed finished face and is provided throughout withirregular intercommunieating pores of variant dimensions which openlypenetrate said exposed finished face, the said material possessing theproperty of absorbing in excess of ten percentum of sounds lying inpitch between middle C and the third octave above middle C.

3. A wall or ceiling for auditoriums and the like, having incombination, a supporting masonry structure, and attached thereto anexposed inner layer of finished masonry sponge-like in structure, thelatter having pores which have rigid walls and are intercommunicatingthroughout the mass and openly penetrate the exposed finished surface,the saidcpores being of such proportional and variant dimensions thatsaid inner masonry material possesses the property of absorbing inexcess of ten percentum of sounds lyingin pitch between middle C and thethird octave above middle C.

4. A sound absorbing ceramic material having a finished surface whichwhen in place forms the finished exposed Wall or ceiling surface, suchmaterial being spongelike in structure and provided with irregular poreswhich intercommunicate and openly penetrate the exposed finished face orfaces of such material and permit the transmission of sound into theinterior of such material and provide means for the absorption thereof.

Signed at New York in the county of New York and State of New York this7th day of February, A. D. 1913.

WALLACE CLEMENT SABINE. ,RAFAEL GUASTAVINO. Witnesses:

T. M. TrrUs, VIOLA E. HUGHES.

